Chameleon signatures are non-interactive signatures based on a hash-and-signparadigm, and similar in efficiency to regular signatures. The distinguishing characteristic of chameleon signatures is that their are non-transferable, with only the designated recipient capable of asserting its validity. In this talk, we introduce the first identity-based chameleon hash function. The general advantages of identity-based cryptography over conventional schemesrelative to key distribution are even more pronounced in a chameleon hashing scheme, because the owner of a public key does not necessarily need to retrieve the associated secret key. We use the identity-based chameleon hashing scheme to build the id-based chameleon signature and a novel sealed-bid auction scheme that is robust, communication efficient (bidders send a single message), and secure under a particular trust model. This is a joint work with Breno de Medeiros. It will appear in the Proc. of Financial Cryptography 2004, Key West, Florida, USA.